1. Field of the Invention
The present invention relates to an open/close control system for controlling the opening and closing operations of a slide door, which is mounted on the side of a vehicle body and driven by a drive source, e.g., a motor, in accordance with an inclination of the slide door produced when the vehicle is vertically inclined with respect to the longitudinal axis of the vehicle body, viz., when the vehicle stops on a sloping road.
2. Description of the Related Art
There is known an open/close control system for a vehicle slide door in which a slide door is mounted on the side of a vehicle body while being slidable in the lengthwise direction of the vehicle body, and is opened and closed by a drive source, e.g., a motor. An operating means is provided close to the driver's seat or a door handle. To open or close the slide door, a driver or any other occupant operates the operating means. In turn, the drive source is driven to move the slide door for its opening and closing.
The slide door is heavy, and moves linearly and in the lengthwise direction of the vehicle body. Therefore, when the vehicle body is vertically inclined with respect to the longitudinal axis of the vehicle body, the drive force to move the slide door is greatly varied.
When the vehicle is on a steep upward slope, a large drive force is required to move or slide the slide door in the upward direction. When the vehicle is on a flat road, a little force is required for the same purpose. When the vehicle is on a steep downward slope, a braking force, not the drive force, is required for sliding the slide door.
When the force, which is capable of moving the slide door being located on a steep slope in the upward direction, is used for moving the slide door in the upward direction, the force is too large to move the slide door in the horizontal or downward direction. A measure taken for this problem by the conventional technique is to control the force for moving or sliding the slide door in accordance with a door moving speed detected. This prior control usually uses a time delay technique for suppressing a hunting in the door movement. In a situation where the vehicle stops on a steep downward slope and its slide door is slid or moved downward direction, upon the start of door movement, the door rushes forward before the open/close control system operates.
When the vehicle is on a steep upward slope, to move its slide door in the upward direction, it is desirable to use a small drive force from the first in controlling the opening/closing operation of the door. To this end, it is very important to know an inclination of the vehicle body in the opening/closing control.
An open/close control system for a vehicle slide door is known in which when the slide door is manually moved, the control device detects the manual operation for the slide door and drives the drive motor to move or slide the door for its opening or closing. Specifically, the control device detects that a distance the slide door is manually moved reaches a preset value of distance or a moving speed of the slide door reaches a preset value of speed, and drives the motor to turn in such a direction as to move the door in the same direction as the moving direction of the manually moved door.
When the vehicle equipped with such a control device stops on a slope, a large force is required to manually move the slide door of the vehicle upward. Therefore, when the door is moved in the upward direction on the slope, it is desirable to quickly shift a control mode of the control device to a motor-driven control mode. One possible measure to obtain a quick shift of the control mode is to set the preset distance and the preset speed at small values. To this end, the necessity is to know a degree of inclination of the vehicle body before the open/close control for the slide door is exercised.